This invention relates to a method for the evaluation of image contrast quality in a single image in an automated optical system. More particularly, the present invention relates to evaluation of image contrast quality in an automated biological screening system, such as a system for analyzing cytological specimens stained according to the Papanicolaou stain process.
In automated optical systems, good image contrast quality promotes good image quality. Good image quality is key to the performance of any imaging application. As a result, it is very important to establish a reliable method to measure image contrast quality of acquired imagery. Such an image contrast quality measure may be used to determine the success of automated image acquisition and may trigger image reacquisition if image contrast quality is not acceptable. Suitable image quality is particularly important for an automated biological specimen screening system. Image contrast quality measurement is, therefore, also important for evaluating performance of such an automated biological specimen screening system.
Therefore, it is a motivation of the present invention to evaluate image contrast quality by measuring the changes in image edge contrast performed on a single image. Measurement of change in image edge contrast is normalized by the edge contrast to achieve image content independence. Additional operations of the present invention further condition the image and remove noise and cluttering to improve the reliability of the image contrast quality measurement.
The image contrast quality measurement employed by the present invention is designed to achieve consistent image contrast quality scoring for a wide range of image contents. It is designed to perform image contrast quality measurement based only on a single image rather than using the relative contrast between multiple images of the same field of view (FOV) acquired at different focus positions. Additionally the invention provides for the utilization of images acquired from biological specimens as well as the utilization of the image contrast scores from all images of a specimen for the evaluation of the processing effectiveness of an automated biological specimen screening system to the specimen.